Deformation analysis of tilted primary mirror for an off-axis beam compressor

James H. Clark, F E Penado, Joel Dugdale

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The Navy Prototype Optical Interferometer (NPOI), located near Flagstaff, Arizona, is a ground-based interferometer that collects and transports stellar radiation from six primary flat collectors, known as siderostats, through a common vacuum relay system to a beam combiner where the beams are combined, fringes are obtained and modulated, and data are recorded for further analysis. The current number of observable stellar objects can increase from 6,000 to approximately 47,000 with the addition of down-tilting beam compressors in the optical train. The increase in photon collection area from the beam compressors opens the sky to many additional and fainter stars. The siderostats are capable of redirecting 35 cm stellar beams into the vacuum relay system. Sans beam compressors, any portion of the beam greater than the capacity of the vacuum transport system, 12.5 cm, is wasted. Engineering analysis of previously procured as-built beam compressor optics show the maximum allowable primary mirror surface sag, resulting in λ/10 peak-to-valley wavefront aberration, occurs at 2.8° down-tilt angle. At the NPOI operational down-tilt angle of 20° the wavefront aberration reduces to an unacceptable λ/4. A design modification concept that reduces tilt-induced sag was investigated. Four outwardly applied 4-lb forces on the rear surface of the mirror reduce the sag from 155 nm to 32 nm at 20° down-tilt and reduce peak-to-valley wavefront deviation to λ/8.6. This preliminary effort indicates that this solution path is a viable and economic way to repair an expensive set of optical components. However, it requires further work to optimize the locations, magnitudes, and quantity of the forces within this system and their influence on the mirror surface.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Volume8125
DOIs
StatePublished - 2011
EventOptomechanics 2011: Innovations and Solutions - San Diego, CA, United States
Duration: Aug 22 2011Aug 25 2011

Other

OtherOptomechanics 2011: Innovations and Solutions
CountryUnited States
CitySan Diego, CA
Period8/22/118/25/11

Fingerprint

Compressor
compressors
Compressors
Mirror
Mirrors
Wavefronts
Interferometers
mirrors
Vacuum
Tilt
Aberrations
Interferometer
Wave Front
navy
interferometers
relay
Aberration
vacuum
Relay
Stars

Keywords

  • Beam compressor
  • Finite element analysis
  • Gravity induced sag
  • Non-symmetric mirrors
  • NPOI
  • Off-axis optics
  • Optical interferometry
  • Tilted mirror deformations

ASJC Scopus subject areas

  • Applied Mathematics
  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Clark, J. H., Penado, F. E., & Dugdale, J. (2011). Deformation analysis of tilted primary mirror for an off-axis beam compressor. In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 8125). [81250C] https://doi.org/10.1117/12.894167

Deformation analysis of tilted primary mirror for an off-axis beam compressor. / Clark, James H.; Penado, F E; Dugdale, Joel.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8125 2011. 81250C.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Clark, JH, Penado, FE & Dugdale, J 2011, Deformation analysis of tilted primary mirror for an off-axis beam compressor. in Proceedings of SPIE - The International Society for Optical Engineering. vol. 8125, 81250C, Optomechanics 2011: Innovations and Solutions, San Diego, CA, United States, 8/22/11. https://doi.org/10.1117/12.894167
Clark JH, Penado FE, Dugdale J. Deformation analysis of tilted primary mirror for an off-axis beam compressor. In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8125. 2011. 81250C https://doi.org/10.1117/12.894167
Clark, James H. ; Penado, F E ; Dugdale, Joel. / Deformation analysis of tilted primary mirror for an off-axis beam compressor. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8125 2011.
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